I always thought Obelix was named after obelisks because of the menhir connection (e.g. both are upright stone monuments of a sort).

The connection with asterisk/Asterix makes it so much better.

FWIW, I only realized last year, ~30 years after I read the books, that Idefix was named thus because of "idée fixe"[0].

Ah, the unexpected depth of a children comic book!

[0] https://en.wiktionary.org/wiki/id%C3%A9e_fixe