Testing and moving directory – clarification needed

Newby alert 😉
I’ve read what I can find in the Codex and forums on this, but I’m still unsure so I’d appreciate some further guidance.

I plan to use WP to replace an exisiting static site.

I think my best option is to install WP in a subdirectory:
‘www.example.com/wordpress’ and develop the site there.

Then, when development is finished I’d like to keep the core files in that subdirectory, but ‘move the blog’ to the root directory so it can be accessed from:
‘www.example.com’

I don’t think any of the examples in the Codex quite fit this scenario – they talk about moving the core files from the root into a subdirectory – so can someone kindly tell me what I’d need to do to achieve this?

Many thanks