Starting again, The Sewing Lawyer cut a length of ribbon which is the full length of the upper sleeve seam of the lining, and another to match the lining's under sleeve seam. On the ribbon, she marked the points from the lining pattern where the jacket sleeve would attach. Then, she marked the points along the upper sleeve seam of the jacket where it will attach to the ribbon.
That's better! I still think the sleeve hem is too loose, but the folds seem to be falling properly now.
Here's what it looks like on the inside (just pinned) for your information. I will hand-tack the ribbon starting at the neck along the shoulder until the two layers need to separate for the top fold, then at each of the four attachment points, and finally at the hem. Under the arm, I'll attach at the under-arm seam, the four attachment points, and the hem.