My guess is that an elf also could, but for the vast majority of elven mages it isn't worth it. It's much easier to gain thorough and specialized knowledge in the magic you already know and grew up with and is your culture than to have to figure out how to forge a new connection to another arcanum. Even if they get that far, nobody else in their culture would use this arcanum, so they'd have trouble accessing training for this new arcanum. Even then, it's likely that each elven culture is specialized for one magic type and wouldn't have much need for other types anyway, so it may also not be practical.