The answer above is incorrect.
In accordance with the prior aswer, I assumed my Riolu would start with base 140 friendship because it is double Riolu's base 70 friendship without the Luxury Ball. I performed various friendship boosting activities to acquire +80 friendship value (Luxury Ball and Soothe Bell boosts already calculated and included).
140+80=220=The friendship value needed to evolve Riolu into Lucario.
So I leveled up Riolu during daytime. He didn't evolve.
Sure enough after adding an additional 70 friendship values, Riolu evolved after gaining another level. This means that the Luxury Ball does not double base happiness, but instead doubles the happiness value. As it turns out, the Luxury Ball will always boost friendship gain after the initial capture, but the capture itself does not change base happiness. In short, all trades in Gen 6 reset base happiness unless the Pokemon is returning to a previous owner that gained/lost values, and the Luxury ball's capture friendship boost only influences the trainer that caught the Pokemon.
Through reading additional sources, I have found evidence that correlates with my study:
Calculating Friendship Values and Gen 3-6 Friendship Trading-
http://bulbapedia.bulbagarden.net/wiki/Friendship
Information Regarding "Base Friendship" and Riolu's Base Friendship-
http://bulbapedia.bulbagarden.net/wiki/List_of_Pokémon_by_base_friendship
Riolu's Base Friendship and How to Evolve Riolu (daytime factor)-
http://pokemondb.net/pokedex/riolu
Gen 3-6 "Default Reset Value" (after trade) and secondary source to Calculating Friendship Values (to make sure Bulbapedia is correct)-
http://www.smogon.com/ingame/misc/dpp_tips
If anyone has done a similar study after Gen 3 involving a Happiness Pokemon caught in a Luxury Ball and traded, and still has a recorded data table of actions and friendship yield, it can be used as evidence for this answer. I would have used my own, but since I didn't keep the original 140 (actually 70) to 220, I cannot supply a complete data table.
