"When will the police arrive?"

Translation: 警察什么时候会到？

[hippietrail]

Shouldn't "什么时候警察会到" also be correct?

[thedr9wningman]

I totally have questions and issues about where to place the "when" in Mandarin. Is there a rule I can reference?
Yours looks like a decent "topic-comment" construction to me.

[Damien2711]

Yes and it is accepted.

[qaXer]

警察哪时候会到?