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

(571) And (remember) the Day when He will gather them all together, then He will say to the angels: "Was it you that these people used to worship?"

(572) And when Our Clear Verses are recited to them, they say: "This (Muhammad صلى الله عليه وسلم) is naught but a man who wishes to hinder you from that which your fathers used to worship." And they say: "This (the Qur'an) is nothing but an invented lie." And those who disbelieve say of the truth when it has come to them (i.e. Prophet Muhammad صلى الله عليه وسلم when Allah sent him as a Messenger with proofs, evidence, verses of this Qur'an, lessons, signs, etc.): "This is nothing but evident magic!"

(573) And if you could but see, when they will be terrified with no escape (for them), and they will be seized from a near place.

(574) And they swore by Allah their most binding oath that if a warner came to them, they would be more guided than any of the nations (before them); yet when a warner (Muhammad صلى الله عليه وسلم) came to them, it increased in them nothing but flight (from the truth)

(575) And if Allah were to punish men for that which they earned, He would not leave a moving (living) creature on the surface of the earth; but He gives them respite to an appointed term: and when their term comes, then verily, Allah is Ever All-Seer of His slaves.

(576) And put forward to them a similitude: the (story of the) dwellers of the town, [it is said that the town was Antioch (Antakiya)], when there came Messengers to them.

(577) when We sent to them two Messengers, they belied them both; so We reinforced them with a third, and they said: "Verily we have been sent to you as Messengers."

(578) It was said (to him when the disbelievers killed him): "Enter Paradise." He said: "Would that my people knew

(579) And when it is said to them: "Fear of that which is before you (worldly torments), and that which is behind you (torments in the Hereafter), in order that you may receive Mercy (i.e. if you believe in Allah's religion - Islamic Monotheism, and avoid polytheism, and obey Allah with righteous deeds)."

(580) And when it is said to them: "Spend of that with which Allah has provided you," those who disbelieve say to those who believe: "Shall we feed those whom, if Allah willed, He (Himself) would have fed? You are only in a plain error."