Route 5, 6, 7, 9, 10, 11, 12, 15, 16, Dragonspiral Tower, Abundant Shrine, Lostlorn Forest, Village Bridge in the rustling grass.
This information was from this site. If you want to know the locations for any other Pokemon, just go to their page in this list here: http://pokemondb.net/pokedex/all
Or just type in their name and go to their page using this: http://pokemondb.net/search
Also, you can get an Emolga on Route 7 as a in game trade for a Boldore.