Something like that would be easy to convert to a Velcro strap even if you don’t have a sewing machine. You can get something in a fabric store called “double fold bias tape” or “double fold bias binding” (they also make fleece binding if you prefer). It’s no more than 1/2” wide and can easily be stitched on with 4-5 stitches each side in place of elastic. If you have some of those Velcro cord wraps, they would be a better choice than the regular Velcro for this purpose. It’s lower profile and about as wide as the bias binding. Cut and sew a little square or rectangle on each end of your binding to hold your mask around your head.