I don't have a First Edition, or any other early edition. However, my electronic copy does begin with a "Note on the Text", where Douglas Anderson goes over the publishing history. He mentions:I will stick with 'and' instead of 'the' unless I can figure out that J.R.R. changed it. I think we should accord J.R.R. the respect of knowing that he is a careful proof reader, and consider that the word he published was his word, unless we are sure that it was someone else's error, which he later changed.
"In the production of this first volume, Tolkien experienced what became for him a continual problem: printer’s errors and compositor’s mistakes, including well-intentioned ‘corrections’ of his sometimes idiosyncratic usage."
"Tolkien had made a few small corrections, but further errors entered The Fellowship of the Ring in its December 1954 second impression when the printer, having distributed the type after the first printing, reset the book without informing the author or publisher. These include misrepresentations of the original printed text – that is, words and phrases that read acceptably in context, but which depart from Tolkien’s wording as originally written and published."
"For this new edition <the unauthorized, American edition> by Ace Books the text of the narrative was reset, thus introducing new typographical errors; the appendices, however, were reproduced photographically from the hardcover edition, and remain consistent with it."
It wasn't until 1966 that the revised text was published, and even then, there were further corrections which Tolkien was making but didn't manage to submit in time for publication of that volume. Most of these issues appear to have been in the appendices, but there were some in the text as well. Whether the line in question was changed at this time or not, this discussion reminds me that errors could not only arise from the author, but also from the publisher, as they had to take the text and set it.
"Loth was my father to give me leave, and long have I wandered by roads forgotten, seeking the house of Elrond, of which many had heard, but few knew where it lay." It sounds like Boromir is explicitly using Elrond's name in asking directions. Granted, that's not an exact quote, but the only other way I can see to take that would be that "Imladris" and "house of Elrond" are so synonymous that he doesn't feel a distinction needs to be made.I agree that Boromir is seeking out 'Elrond' and 'Halfelven' as he travels north, since they have been associated to Imladris by Denethor. Imladris, however, is in the poem, and Elrond is not. So Imladris is what he is primarily seeking. That's probably one of his problems, in that there might be many people who have some idea where Rivendell is, but don't know the name 'Imladris'. He might have better luck asking if people have heard of someone called Elrond.
I find it very unlikely that there is any confusion over Elrond's identity. Even if the blood of Numenor is waning, it is not yet spent; and stewards and kings, at least, should still be remembered. Elrond is the brother of Elros, who was the first king of Numenor. I find it almost certain Denethor knows this, and Boromir may very well know it too, considering his interests.Sure, he might consider the possibility that Elrond is an Elf, or Wizard, and might still be alive, but equally, Elrond might have been a Man, long departed from Middle Earth.