There is no formal definition of any of them - the only such course recognised as part of the licencing process is MCC.
However, it is generally accepted that LOFT training is SOP/route training (performed in a simulator or aeroplane) to build experience. It is not exclusive to jets - hence the lack of "Jet" in the title.
Jet Orientation Course/Training usually combines LOFT with hands-on jet flying to prepare for the particularly big step from light pistons to jets.
All may include the MCC syllabus to qualify for the issue of an MCC certificate but the actual syllabus and SOPs used will usually be determined by the sponsor airline or training provider.
To be honest, for the advert, I would expect that they are really talking about MCC because you can not complete a multipilot type rating until you have completed an MCC.