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

(511) And when he arrived at the water (a well) of Madyan (Midian) he found there a group of men watering (their flocks), and besides them he found two women who were keeping back (their flocks). He said: "What is the matter with you?" They said: "We cannot water (our flocks) until the shepherds take (their flocks). And our father is a very old man."

(512) Then there came to him one of the two women, walking shyly. She said: "Verily, my father calls you that he may reward you for having watered (our flocks) for us." So when he came to him and narrated the story, he said: "Fear you not. You have escaped from the people who are Zalimun (polytheists, disbelievers, and wrong-doers)."

(513) Then, when Musa (Moses) had fulfilled the term, and was travelling with his family, he saw a fire in the direction of Tur (Mount). He said to his family: "Wait, I have seen a fire; perhaps I may bring you from there some information, or a burning fire-brand that you may warm yourselves."

(514) So when he reached it (the fire), he was called from the right side of the valley, in the blessed place, from the tree: "O Musa (Moses)! Verily I am Allah, the Lord of the 'Alamin (mankind, jinn and all that exists)!

(515) "And throw your stick!" But when he saw it moving as if it were a snake, he turned in flight, and looked not back. (It was said:) "O Musa (Moses)! Draw near, and fear not. Verily, you are of those who are secure.

(516) Then when Musa (Moses) came to them with Our Clear Ayat (proofs, evidence, verses, lessons, signs, revelations, etc.), they said: "This is nothing but invented magic. Never did we hear of this among our fathers of old."

(517) And you (O Muhammad صلى الله عليه وسلم) were not on the western side (of the Mount), when We made clear to Musa (Moses) the commandment, and you were not among the witnesses.

(518) And you (O Muhammad صلى الله عليه وسلم) were not at the side of the Tur (Mount) when We did call: [it is said that Allah called the followers of Muhammad صلى الله عليه وسلم, and they answered His Call, or that Allah called Musa (Moses)]. But (you are sent) as a mercy from your Lord, to give warning to a people to whom no warner had come before you: in order that they may remember or receive admonition. [Tafsir At-Tabari].

(519) But when the truth (i.e. Muhammad صلى الله عليه وسلم with his Message) has come to them from Us, they say: "Why is he not given the like of what was given to Musa (Moses)? Did they not disbelieve in that which was given to Musa (Moses) of old? They say: "Two kinds of magic [the Taurat (Torah) and the Qur'an], each helping the other!" And they say: "Verily in both we are disbelievers."

(520) And when it is recited to them, they say: "We believe in it. Verily, it is the truth from our Lord. Indeed even before it we have been from those who submit themselves to Allah in Islam as Muslims (like 'Abdullah bin Salam and Salman Al-Farisi).