He simply said that he would draw ALL to himself. To find out what the all is, we look at the previous verse, where he speaks of the judgment of the world.
In verse 31 Christ talks about the judgement of the world; He particularly mentions the prince of this world (Satan): "Now is the judgment of this world: now shall the prince of this world be cast out." (joh 12:31) This says to me that His 'lifting up' is
the judgement against Satan. It is the judgement against Satan which is now; the battle for the bruised heal and bruised head has commenced and will end with "it is finished": consumatum est (it is finished) was the cheer Roman Legionnaires shouted at the end of a victorious battle. Because it is this battle which is finished, Paul can then say "There is therefore now
no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit." ( Rom 8:1)
Notice that the text does not say, as is traditionally interpreted, that he would begin a process of dragging, or start to drag, or drag over time, but rather that, when he was lifted up, AT THAT TIME, all would be dragged to him. If that all is the judgment of the world, then that judgment is part of that which he pronounced as 'it is finished'.
May I respectfully submit He didn't say that this would happen 'when' He was lifted up, rather He said 'if I be lifted up': "And I, if I be lifted up from the earth, will draw all men unto me." (Joh 12:32) It is the act of being lifted up which starts things, not when that act takes place. Christ is talking about the consequences of the act, not the time of the act.
We are also not however, limited in our use of the word 'when' to refer exclusively to time. I could say, for example, "when you hit your finger with a hammer it will hurt". I am not using 'when' here to mean a specific time, I am use 'when' to show consequence. I could just as easily have said "if you hit your finger with a hammer it will hurt." So, I respectfully disagree with your assertion that Christ must
by definition be referring to the timing of an event.
May I suggest that Jesus did not say he would drag or draw all MEN or PEOPLE to himself, but their judgment. I say this because the word 'men' and 'people' has been inserted into the text.
The 'men' was added because it was implied in the Greek. When we talk about the quick and the dead, it is implied in English that we are talking about the quick people and the dead people. Were it 'all', Christ would draw black holes, rocks, sticks etc to Him. Why would He need to do that? Translations are tricky, but I don't think adding a noun in one language to clarify meaning in another can be used to changes the whole timbre of a sentence. When James Joyce entitled his short story The Dead
, it was implied the story was about people.