How important is the the method of casting off stitches on a top down sleeve with a lace edging?
Apparently very important. I originally cast off both of the sleeves in the usual manner by knitting two sts and lifting the first st over the second and off the needle. This is how it ended up looking - rolled which was not what I wanted.
After the sweater was all finished I went back to the sleeve and pulled out the cast off row and picked up the stitches one stitch at a time. This time I cast off in the lace pattern. This is how it ended up looking - flat which was what I wanted.
Here is the beginning of the new sweater.
p.s. Don't worry socks, I haven't forgotten you.