The word(s) "when" appears 916 time(s) in 828 verse(s) in Quran in Mohsin Khan translation.

(631) Then when their Messengers came to them with clear proofs, they were glad (and proud) with that which they had of the knowledge (of worldly things). And that at which they used to mock, surrounded them (i.e. the punishment).

(632) So when they saw Our punishment, they said: "We believe in Allah Alone and reject (all) that we used to associate with Him as (His) partners.

(633) Then their Faith (in Islamic Monotheism) could not avail them when they saw Our punishment. (Like) this has been the way of Allah in dealing with His slaves. And there the disbelievers lost utterly (when Our Torment covered them).

(634) Then He rose over (Istawa) towards the heaven when it was smoke, and said to it and to the earth: "Come both of you willingly or unwillingly." They both said: "We come willingly."

(635) when the Messengers came to them, from before them and behind them (saying): "Worship none but Allah", they said: "If our Lord had so willed, He would surely have sent down the angels. So indeed we disbelieve in that with which you have been sent."

(636) Till, when they reach it (Hell-fire), their hearing (ears) and their eyes, and their skins will testify against them as to what they used to do.

(637) And among His Signs (in this), that you see the earth barren; but when We send down water (rain) to it, it is stirred to life and growth (of vegetations). Verily, He Who gives it life, surely, is Able to give life to the dead (on the Day of Resurrection). Indeed He is Able to do all things.

(638) Verily, those who disbelieved in the Reminder (i.e. the Qur'an) when it came to them (shall receive the punishment). And verily, it is an honourable well-fortified respected Book (because it is Allah's Speech, and He has protected it from corruption. (See V.15:9)

(639) To Him (Alone) is referred the knowledge of the Hour. No fruit comes out of its sheath, nor does a female conceive nor brings forth (young), except by His Knowledge. And on the Day when He will call unto them (polytheists) (saying): "Where are My (so-called) partners (whom you did invent)?" They will say: "We inform You that none of us bears witness to it (that they are Your partners)!"

(640) And when We show favour to man, he withdraws and turns away; but when evil touches him, then he has recourse to long supplications.