Who can sing the blues?
Round-waisted hobbits can't sing the blues... unless they be in the Lockholes.
Under no conditions may a Mirkwood elf sing the blues.
Thain's descendants can sing the blues, especially while mining iron or coal.
Radbug can sing the blues once he's blind, especially since he's fixin' to die. Only he gotta sing quick.
Generally speaking the only elves that can sing the blues are the ones forever banned from the West. And elves that are fixin' to die can't sing the blues either; they're just getting relocated. And no singing in Mandos' halls, blues or not. Dead elves can't sing the blues.