Should I place a question mark after "Can you (just) imagine"?

Question

I mean should I always split the sentence into two ("And can you imagine? He escaped through the window!") or I can just get away with one long sentence without a question mark at all (something like "And can you just imagine - he escaped through the window!"). What punctuation would be correct in such cases?

Answer 1

You should end the the first statement with a question mark and begin the second with a capital letter. This is the correct way of phrasing. Some people use a comma to split the sentence if they consider them as clauses but this is quite uncommon.