The word(s) "when" appears 708 time(s) in 647 verse(s) in Quran in Abdullah Yusuf Ali translation.

(151) when some of them said: "Why do ye preach to a people whom Allah will destroy or visit with a terrible punishment?"- said the preachers:" To discharge our duty to your Lord, and perchance they may fear Him."

(152) when they disregarded the warnings that had been given them, We rescued those who forbade Evil; but We visited the wrong-doers with a grievous punishment because they were given to transgression.

(153) when in their insolence they transgressed (all) prohibitions, We said to them: "Be ye apes, despised and rejected."

(154) when We shook the Mount over them, as if it had been a canopy, and they thought it was going to fall on them (We said): "Hold firmly to what We have given you, and bring (ever) to remembrance what is therein; perchance ye may fear Allah."

(155) when thy Lord drew forth from the Children of Adam - from their loins - their descendants, and made them testify concerning themselves, (saying): "Am I not your Lord (who cherishes and sustains you)?"- They said: "Yea! We do testify!" (This), lest ye should say on the Day of Judgment: "Of this we were never mindful":

(156) They ask thee about the (final) Hour - when will be its appointed time? Say: "The knowledge thereof is with my Lord (alone): None but He can reveal as to when it will occur. Heavy were its burden through the heavens and the earth. Only, all of a sudden will it come to you." They ask thee as if thou Wert eager in search thereof: Say: "The knowledge thereof is with Allah (alone), but most men know not."

(157) It is He Who created you from a single person, and made his mate of like nature, in order that he might dwell with her (in love). when they are united, she bears a light burden and carries it about (unnoticed). when she grows heavy, they both pray to Allah their Lord, (saying): "If Thou givest us a goodly child, we vow we shall (ever) be grateful."

(158) But when He giveth them a goodly child, they ascribe to others a share in the gift they have received: but Allah is exalted high above the partners they ascribe to Him.

(159) Those who fear Allah, when a thought of evil from Satan assaults them, bring Allah to remembrance, when lo! they see (aright)!

(160) when the Qur'an is read, listen to it with attention, and hold your peace: that ye may receive Mercy.