Here's a case where English could follow the same question syntax we've set up for Dovahzul. How about, "Thought you could steal from me?"

This may either help or hurt your confusion. Since (most) verbs are the same in past tense and present tense, lorot is both think and thought. So, "Lorot hi vis gahrot nol zey?" could mean both "Think you can steal from me?" and "Thought you could steal from me?" There is the invented word vust for "could" that could help you clarify past tense.

Another thing you could do is "Drey lorot his vis gahrot nol zey?", which is more literal to the original. "Did (you) think you could steal from me?" You would be safe cutting the first "you" here.

But it would be "Think you could steal from me?" since there's no past tense verb for lorot.

Hypothetically if I did want it in the past tense, which I don't, how would I phrase it so? Oh wait... would the differenciation be in the word 'could' or 'can'; 'vust' or 'vis'? If so what if 'might' was used instead of 'could'? As in "Did you think you might steal from me?", or is that complete nonsense? My brain hurts :&

That helps me a lot. Thanking you.