What this POD of yours would seem to require is a North Africa that serves as a successful crusade target. Now, what this would seem to require would be general political and cultural disunity in North Africa.
This could take on a number of forms, from the Berbers choosing to remain
Christian, to the Norman conquest of Sicily and South Italy not happening, thus resulting in South Italy becoming a chaotic region fought over between Arabic raiders and local brigands and strongmen. The Berbers remaining Christian would dramatically increase the overall instabillity of the region, and could make matters of conquest considerably easier for any wannabe crusader who is capable of making an appeal to the Berbers.
Combined with the above premise concerning Italy, this could cause the Pope to start directing Crusading armies south after the success of the First Crusade. The armies would likely be lead by the French, as the English are too far away, the Germans are in the midst of the Investisure Controversy, and the Spanish are a disunited non-factor.
If the French are able to conquer and hold North Africa, then barring the rise of an Islamic power to drive them back into the sea, they should be still holding onto said territory at the date of the premise