Thanks very much for your prompt reply, Jeff.
I’m still a bit puzzled though. If I select an image shot with my Canon 5D and 24-105 L lens and than click enable in the Lens Correction panel, the correct information shows in Make, Model and Profile. When I then click on the Model drop-down, the s90 shows at the bottom of the list.
However, when I select an image shot with the s90 and click on the enable button, Make shows ‘none’ and when I select Canon as the Make, it offers the lens mentioned above (G10) but the Model drop-down doesn’t show the s90 and therefore I cannot enable its profile.