LHC Computing Grid, Worldwide LHC Computing Grid (see WLCG)

Acronyms don't need spelling out for the CERN Courier

Low-Energy Ion Ring

Spell out in first use then use acronym for the CERN Courier

Large Electron–Positron Collider

Acronym doesn't need spelling out for the CERN Courier

Large Hadron Collider

Initial capital letters. Always spell out first time (except in the CERN Courier), with abbreviation in brackets. Use the abbreviation thereafter.

Experiments at the Large Hadron Collider (LHC) suggest...

Beware of tautologies: Don't use "The LHC machine" or "The LHC accelerator", as this is equivalent to saying "The Large Hadron Collider accelerator...", which doesn't mean anything (the LHC doesn't accelerate accelerators).