I'm not sure who decided that these were in style at some time, but I'm not sure a nice "square" arm is a good look. So let's get our refashion shoes on and go!
This is the hard part, making the casing for the elastic. I wanted to make this as easy as possible, so I wanted one seam. Easy peasy. Turn the top of the fabric down about 3"-4" then fold in back on itself. I am not sure how else to describe it. Sew on the fold with the raw edge.
I had to put the dress on my little girl first