[narfforc]

There are numerous occasions in Tolkiens works when he clearly defines what he means by race. His characters speak to each other of it. Aragorn has no difficulty telling Legolas and Gimli, the difference between members of his own race, when explaining he is a Numenorean, and the Rhohirrim are not. So Aragorn has distant kinship through Elros, to Elrond, however Aragorn is no more an Elf than Elros or Eldarion, due to choices made. The Peredhil were given the choice of which kind they wished to be accounted. The reason I believe, was so that there would be no blurring at the edges, there is no middle race, Elf or Man. How this was actually achieved, only the Valar know, for how can you change a thing that is?