The lace is here

I was so happy to receive a soft little package yesterday in the mail from www.lace-mart.com I stitched it  up in the quiet of the evening and now have this:

I like the look of the skirt on the washer.  It just makes me happy and feels right to have my maidservant all dressed up, but the elastic in the casing isn’t working out.  It stretches and sags down.  Any ideas to attach it better?