There's a post somewhere on the Localisation forums about this; I can't be arsed to link it presently but the short version is that right now, the English localisation team has no control over how many dialogue boxes are in a given NPC's speech, and there's no way to cut out subsequent chunks of dialogue in a repeatable quest like Louisoix. This is due to engine limitations and it's something they're going to be working on in 2.0.