I've never ever liked the "you're arms are worked during back and chest/shoulders" argument. It's true they are hit but indirectly hit. However, I don't feel anyone that trains arms this way is training optimally and getting results unless they're a pharmacological specimen.
I usually hit arms all their own, and I have two splits I alternate using depending on volume of my workout and if I'm leaning up or lifting heavier:
Day one: Back and Chest
Day two: Legs (quads, hams and calves)
Day three is rest day
Day four: Shoulders, triceps and biceps.
Day five is a rest day, and day six you repeat the cycle over again, allowing the body to rest and train 5x/wk. Cardio is done for 15min after weights.
The second split I use, allows for more volume per body part, less time in the weight pit and a little more cardio, still done after my weight routine for about 20-25min:
Day one: Back, traps and rear delts
Day two: Chest and abs
Day three: Quads and calves
Day four rest
Day five: Triceps and biceps
Day six: Hamstrings and shoulders
Day seven: rest.