Elbows, maybe if the pain is cartilage related. Forearms, probably not, it works on joint cartilage, and unless you're special, there are no joint in the forearm.
If you have tendonitis or ligament damage look elsewhere (like maybe low dose GH, glucosamine, chondroitan, msm, maybe even certain AAS which affect collagen levels - I think Animal Mass had a post on this, seen it on a bunch of boards).
DrG