"When will you work?"

The word order is not too natural, at least in prose. It looks as if it's taken out of a poem (ко-ли́ бу-де́ш ти пра́-цю-ва́-ти would make a nice iambus — you'd need to add one extra stress, though).

Updated: actually, I've checked and it looks like бу́деш is the standard stress place. I personally seem to use бу́деш and буде́ш interchangeably.

«Коли́ ти буде́ш працюва́ти?» should work, however.