If the break on the arm is clean, you can reattach it with acrylic glue. Weld On 3 or 4 would work, as well as Pro Weld. I prefer Weld On 4, but you can’t get it in California any more. The Pro Weld is awesome - I think the maker has sold off to Micro Mark. They have a version of the Pro Weld which I’ve been using and like quite a bit.
I don’t know if you have used these types of glue, so here’s a little info. Apologies if it’s not necessary. The trick with these types of glue is careful application. They are water thin and as solvent based glues will leave spots if you spatter or go outside the area you want to glue up.
Put a drop of the glue on the joint edges and then carefully position. Hold until you can let go and not have it droop off the joint. Shouldn’t take too long. You can use the brush it comes with, just don’t drip to much onto the joint. Also, you could use a needle bottle to apply it as well. Both options are good, just a matter of your preferences. It’s worth practicing on scraps if you are worried about the technique at all.