BhG 6.4

syntax

yadā hi (indeed when) indriyārtheṣu (in the objects of the senses) karmasu [ca] (and in activities) na anuṣajjate (he is not attached),
sarva-saṁkalpa-saṁnyāsī (renunciant of all desires) tadā (then) yogārūḍhaḥ (one who attained yoga) ucyate (is called).

grammar

yadā	–	av. – when (correlative of: tadā – at that time, then);
hi	–	av. – because, just, indeed, surely;
na	–	av. – not;
indriyārtheṣu	–	indriya-artha 7n.3 m.; TP: indriyāṇām artheṣv iti – in the objects of the senses (from: √ind – to be powerful, indriya – the senses; √arth – to strive to obtain, to desire, to request, artha – purpose, advantage, concern, object, wealth);
na	–	av. – not;
karmasu	–	karman 7n.3 n. – in activities (from: √kṛ – to do);
anuṣajjate	–	anu-√sañj (to attach, to stick, to embrace) Praes Ā 1v.1 – he clings to, is attached;
sarva-saṁkalpa-saṁnyāsī	–	sarva-saṁkalpa-saṁnyāsin 1n.1 m.; TP: sarveṣāṁ saṁkalpānāṁ sanyāsīti – renunciant of all desires (from: sarva – all, whole; sam-√kḷp – to be ready, to wish, saṁ-kalpa – idea, desire; sam-ni-√as – to lay aside, to renounce, to give up, PP saṁnyasta – laid aside, renounced, saṁnyāsin – an ascetic, renunciant; -in, -min, -vin – sufixes meaning one who possesses);
yogārūḍhaḥ	–	yoga-ārūḍha 1n.1 m.; TP: yogam āruḍha iti – who attained yoga (from: √yuj – to yoke, to join, to engage, yoga – yoga, yoking, application, a means, one of the schools of Hindu philosophy; ā-√ruh – to ascend, to rise, PP ārūḍha – who attained);
tadā	–	av. – at that time, then;
ucyate	–	√vac (to speak) Praes. pass. 1v.1 – it is said;

textual variants

anuṣajjate → anusajjate / anurajyate / anuṣajyate (he clings / is shining / is attached);
karmasv anuṣajjate → sarva-karmasv ṣajjate (he clings to all activities);
tadocyate → tad ucyate / tatocyate (that is called / O my dear, it is called);

Śāṃkara

athedānīṃ kadā yogārūḍho bhavatīty ucyate—

yadā samādhīyamāna-citto yogī hīndriyārtheṣv indriyāṇām arthāḥ śabdādayas teṣv indriyārtheṣu karmasu ca nitya-naimittika-kāmya-pratiṣiddheṣu prayojanābhāva-buddhyā nānuṣajjate’nuṣaṅgaṃ kartavyatā-buddhiṃ na karotīty arthaḥ | sarva-saṃkalpa-saṃnyāsī sarvān saṃkalpān ihāmutrārtha-kāma-hetūna saṃnyasituṃ śīlam asyeti sarva-saṃkalpa-saṃnyāsī | yogārūḍhaḥ prāpta-yoga ity etat, tadā tasmin kāla ucyate | sarva-saṃkalpa-saṃnyāsīti vacanāt sarvāṃś ca kāmān sarvāṇi ca karmāṇi saṃnyasyed ity arthaḥ | saṃkalpa-mūlā hi sarve kāmāḥ—saṃkalpa-mūlaḥ kāmo vai yajñāḥ saṃkalpa-saṃbhavāḥ [mātranu 2.3]

kāma jānāmi te mūlaṃ saṃkalpāt tvaṃ hi jāyase |
na tvāṃ saṃkalpayiṣyāmi tena me na bhaviṣyasi || [mātrabh 12.177.25] ity ādi-smṛteḥ |

sarva-kāma-parityāge ca sarva-karma-saṃnyāsaḥ siddho bhavati | sa yathā-kāmo bhavati tat-kratur bhavati yat kratur bhavati tat karma kurute [bhāvātmauttaṃ 4.4.5] ity ādi śrutibhyaḥ | yad yad dhi kurute jantus tat tat kāmasya ceṣṭitaṃ [mātranu 2.4] ity ādi-smṛtibhyaś ca | nyāyāc ca—na hi sarva-saṃkalpa-saṃnyāse kaścit spanditum api śaktaḥ | tasmāt sarva-saṃkalpa-saṃnyāsīti vacanāt sarvān kāmān sarvāṇi karmāṇi ca tyājayati bhagavān

Rāmānuja

kadā pratiṣṭhitayogo bhavatīty atrāha

yadāyaṃ yogī tv ātmaikānubhavasvabhāvatayā indriyārtheṣu ātmavyatiriktaprākṛtaviṣayeṣu, tatsaṃbandhiṣu ca karmasu nānuṣajjate na saṅgam arhati, tadā hi sarvasaṅkalpasamnyāsī yogārūḍha ity ucyate / tasmād ārurukṣor viṣayānubhavārhatayā tadananuṣaṅgābhyāsarūpaḥ karmayoga eva yoganiṣpattikāraṇam / ato viṣayānanuṣaṅgābhyāsarūpaṃ karmayogam eva ārurukṣuḥ kuryāt

Śrīdhara

kīdṛśo ‚yaṃ yogārūḍho yasya śamaḥ kāraṇam ucyata iti ? atrāha yadeti | indriyārtheṣv indriya-bhogyeṣu śabdādiśu tat-sādhaneṣu ca karmasu yadā nānuṣajjate āsaktiṃ na karoti | tatra hetuḥ āsakti-mūla-bhūtān sarvā bhoga-viṣayān karma-viṣayāṃś ca saṅkalpān saṃnyasituṃ tyaktuṃ śīlaṃ yasya saḥ | tadā yogārūḍha ucyate

Madhusūdana

kadā yogārūḍho bhavatīty ucyate yadeti | yadā yasmiṃś citta-samādhāna-kāla indriyārtheṣu śabdādiśu karmasu ca nitya-naimittika-kāmya-laukika-pratiṣiddheṣu nānuṣajjate teṣāṃ mithyātva-darśanenātmano ‚kartr-abhoktṛ-paramānanadādvaya-svarūpa-darśanena ca prayojanābhāva-buddhyāham eteṣāṃ kartā mamaite bhogyā ity abhiniveśa-rūpam anuṣaṅgaṃ na karoti | hi yasmāt tasmāt sarva-saṅkalpa-saṃnyāsī sarveṣāṃ saṅkalpānām idaṃ mayā kartavyam etat phalaṃ bhoktavyam ity evaṃ rūpāṇāṃ mano-vṛtti-viśeṣāṇāṃ tad-viṣayāṇāṃ ca kāmānāṃ tat-sādhanānāṃ ca karmaṇāṃ tyāga-śīlaḥ | tadā śabdādiṣu karmasu cānuṣaṅgasya tad-dhetoś ca saṅkalpasya yogārohaṇa-pratibandhakasyābhāvād yogaṃ samādhim ārūḍho yogārūḍha ity ucyate

Viśvanātha

samyak-śuddha-cittas tu yogārūḍhas taj-jñāpakaṃ lakṣaṇam āha yadeti | indriyārtheṣu śabdādiṣu karmasu tat-sādhaneṣu

Baladeva

yogārūḍhatva-jñāpakaṃ cihnam āha yadeti | indriyārtheṣu śabdādiṣu tat-sādhaneṣu karmasu ca yadātmānanda-rasikaḥ san na sajjate | tatra hetuḥ sarveti | sarvān bhoga-viṣayān karma-viṣayāś ca saṅkalpānāsattimūla-bhūtān saṃnyasituṃ parityaktuṃ śīlaṃ yasya saḥ