All 3 Uses of

however
in
The Lion, the Witch and the Wardrobe

I should not be at all surprised to find that the other world had a separate time of its own; so that however long you stayed there it would never take up any of our time.
p. 54.1 *

however long = regardless of how

Anyway, she'll be better than that awful Aslan! At least, that was the excuse he made in his own mind for what he was doing. It wasn't a very good excuse, however, for deep down inside him he really knew that the White Witch was bad and cruel.
p. 97.2 *

however = though (used to connect contrasting ideas)

And however the dwarf whipped the poor reindeer the sledge went slower and slower.
p. 128.8

however = regardless of how much

Definitions:

(1) (however as in: However, complications may...)
though (or another expression that connects contrasting ideas)

(Based on idea 1 we might not expect idea 2, but this is a way of saying that even though idea 1 exists, we still have idea 2. Synonyms include in spite of that, despite that, nevertheless, nonetheless, on the other hand, in contrastand but.)
(2) (however as in: However much she tried...)
to whatever degree (regardless of how much; or whatever unspecified amount)
(3) (however as in: However you do it, get it done!)
in whatever way
(4) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

Much more rarely (and arguably incorrectly), however can be used to intensify the word how, as when one says "However did you find her?" Grammarians would suggest using two words for that usage: "How ever did you find her?"