On the Airbus, the aircraft will not intercept the G/S without being bolted to the localizer. In terms of where it intercepts is based on where the aircraft is in space.
For example in the aircraft is 2000ft AGL at 10 miles, it will track the LOC until it gets to just over 6 miles (assuming a 3 degree glide 318ft per mile) and the aircraft will descend down the G/S provided it is armed. However, if the aircraft is at 4000ft AGL and the aircraft is just over 12 miles, again assuming a 3 degree glide, as long as the aircraft displaced correctly vertically, and the glide slope is armed the aircraft will descend on the glide slope. It wont wait until the FAP. Remember a FAF is associated with non precision approaches
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Hope that helps.