I would consider this comparable to the filtering up we do on the right at lights. I doubt the law covers it, so it's a case by case judgement call.

If there's a long light which I don't expect to change immediately, I'll go up on the right and position myself to make a super wide left letting motor traffic turn inside of me, while I head for the far left corner of the cross street. Other times, I'll take my place in line.

The one thing I don't do is ride to the front, then make the turn in the lane proper trapping those who were there first behind me.

When I expect the light to change before the left turn lane empties, I'll stay far right and make what I call a Copenhagen left (far right corner, wait for light and proceed with cross traffic).

BTW- it's not reasonable to expect laws that cover every possible circumstance. Many decisions have to be made on the basis of common sense and courtesy.