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

(21) And (O Children of Israel, remember) when We took your covenant and We raised above you the Mount (saying): "Hold fast to that which We have given you, and remember that which is therein so that you may become Al-Muttaqun (the pious - See V.2:2).

(22) And (remember) when Musa (Moses) said to his people: "Verily, Allah commands you that you slaughter a cow." They said, "Do you make fun of us?" He said, "I take Allah's Refuge from being among Al-Jahilun (the ignorant or the foolish)."

(23) And (remember) when you killed a man and fell into dispute among yourselves as to the crime. But Allah brought forth that which you were hiding.

(24) And when they (Jews) meet those who believe (Muslims), they say, "We believe", but when they meet one another in private, they say, "Shall you (Jews) tell them (Muslims) what Allah has revealed to you [Jews, about the description and the qualities of Prophet Muhammad صلى الله عليه وسلم, that which are written in the Taurat (Torah)] , that they (Muslims) may argue with you (Jews) about it before your Lord?" Have you (Jews) then no understanding?

(25) And (remember) when We took a covenant from the Children of Israel, (saying): Worship none but Allah (Alone) and be dutiful and good to parents, and to kindred, and to orphans and Al-Masakin (the poor), and speak good to people [i.e. enjoin righteousness and forbid evil, and say the truth about Muhammad صلى الله عليه وسلم], and perform As-Salat (Iqamat-as-Salat), and give Zakat. Then you slid back, except a few of you, while you are backsliders. (Tafsir Al-Qurtubi).

(26) And (remember) when We took your covenant (saying): Shed not the blood of your (people), nor turn out your own people from their dwellings. Then, (this) you ratified and (to this) you bear witness.

(27) And indeed, We gave Musa (Moses) the Book and followed him up with a succession of Messengers. And We gave 'Îsa (Jesus), the son of Maryam (Mary), clear signs and supported him with Ruh-ul-Qudus [Jibrael (Gabriel عليه السلام)]. Is it that whenever there came to you a Messenger with what you yourselves desired not, you grew arrogant? Some you disbelieved and some you killed.

(28) And when there came to them (the Jews), a Book (this Qur'an) from Allah confirming what is with them [the Taurat (Torah) and the Injeel (Gospel)], although aforetime they had invoked Allah (for coming of Muhammad صلى الله عليه وسلم) in order to gain victory over those who disbelieved, then when there came to them that which they had recognised, they disbelieved in it. So let the Curse of Allah be on the disbelievers.

(29) And when it is said to them (the Jews), "Believe in what Allah has sent down," they say, "We believe in what was sent down to us." And they disbelieve in that which came after it, while it is the truth confirming what is with them. Say (O Muhammad صلى الله عليه وسلم to them): "Why then have you killed the Prophets of Allah aforetime, if you indeed have been believers?"

(30) And (remember) when We took your covenant and We raised above you the Mount (saying), "Hold firmly to what We have given you and hear (Our Word)." They said, "We have heard and disobeyed." And their hearts absorbed (the worship of) the calf because of their disbelief. Say: "Worst indeed is that which your faith enjoins on you if you are believers."