There is a possibility that Christopher mistook Alkarondas as Elvish and attempted to "normalize" the spelling with "c". However if it was really Adunaic, it should have remained with "k" according to App. E.
Still the form of the word is curiously compatible with Quenya. Also it must be one of the very few Adunaic words that has no circumflex. Sage 10:28, 6 April 2020 (UTC)