Sounds fun. I like the epic scope of the campaign. My advice would to get one of the scrolls whose alignment corresponds to the party's alignment in the hands of theplayers. I would make this a chance encounter to increase the "fate" factor involved. The best way I think is that the PC's see a suspicious looking person with injuries stalking in a dark city street. 100 feet away, a group of elves are obviously looking for the individual. The elves see the person and shoot him down. The party can interject in this scenario whenever they want too. The person is carrying one of the scrolls. If the PC's allow the elves to gain possesion of it....
Just my$.02.
Just my$.02.