Hi, I've had my cactus for nearly 25 years. It's a cleistocactus - but what kind?

Here's a photo: http://web2k.co.uk/poASD45gk_4rff/1180271582.jpg

It has never flowered - is it supposed to?

I never know how much water to give it - it only seems to grow after i've watered it.

I only water it between say mid March to mid October - is this ok?

It seems to produce new branches but the original trunk has stopped growing and the branches are now actually taller. Is this normal?

Thanks for any replies.

Cactus.

No replies - does nobody know anything about cacti??