There was an article in this months Hel Achau - Clwyd FHS magazine.
Can't remember the exact details, but will try and give the gist from memory.
Lodges tended to have fanciful names. Anybody could apply to join a lodge, but they were initially for qualified tradesmen.
They were charitable institutions, who were driven underground during WW2, and recently made a concious decision to "open up".
Other similar organisations are Oddfellows.