One of the oddest things about usage books is their penchant for assuring readers that really, the things people often get wrong are very, very simple. Lie, lay, lain? No problem! Spelling its and it's correctly? It's a snap! Lose vs. loose? Duh! You'd think these writers would grasp that if getting it right were so easy, it wouldn't be wrong (or "wrong") so often.
So it was refreshing to come across a language maven's more realistic assessment of the lose-loose problem. Says Henry Alford, dean of Canterbury, in "A Plea for the Queen's English" (1864):
I have several times noticed, and once in a letter censuring some of my own views on the Queen's English, the verb to lose spelt loose. A more curious instance of the arbitrary character of English usage as to spelling and pronunciation, could hardly be given, than these two words furnish: but usage must be obeyed. In this case it is not consistent with itself in either of the two practices: the syllable "-ooze" keeps the sound of "s" in loose, noose, goose, but changes it for that of "z" in choose: the syllable "-ose'' keeps the sound of "s" in close, dose, but changes it for that of "z" in chose, hose, nose, pose, rose. But when usage besides this requires us to give the "o" in lose the sound of "u" in luminary, we feel indeed that reasoning about spelling and pronunciation is almost at an end.