In #1020, we saw an example of where a Québécois speaker in Montréal said:
quand qu’y’a fermé la porte
(an informal variation on quand il a fermé la porte)
when he closed the door
Instead of saying just quand, she said quand que. This is a feature of colloquial language. It’s not necessary for you to include this que yourself here, but it’s always good to understand what people are saying.
It’s not just after quand that you might hear que added in. I heard another example of it today, this time using comment instead:
comment qu’y pensaient
(an informal variation on comment ils pensaient)
how they used to think
Remember, il and ils are pronounced informally as i’, often written as y.