Why does McCarthy wait until this point in the story to reveal the orchard keeper's formal name?

It is probably not a coincidence that Arthur Ownby is finally named only when he is forced to directly come into contact with the law. Ownby wants nothing more than to be his own man, free from any ties to the community and especially from any ties to the government. As has been discussed regarding previous chapters, Ownby's anonymity--he is often only referred to as "the old man"--might be interpreted as a sign of this isolation, insofar as names are a sign of one's social existence. Thus, when the police come to his house, Ownby is forced to face the reality that he is part of a larger community and, therefore, he is finally given a name.