Unless the weather is bad, try keeping Luke out at least 15 minutes or so when you take him out. Make it a fun time for him so he won't dread it and you'll have a better chance of having him "ask" to go out when he needs to go. Try not to get too frustrated, though, because it may take awhile before he completely stops using the floor as soon as you bring him in. If you still have problems after a week or so, then when he has an accident, try putting him in an enclosed space, like the bathroom, by himself for 10 minutes or so. The worst thing you can do to Luke is to ignore him, so that might be the best deterrent. We had to start putting Shiva in the laundry room when she had an accident, but after several days, she caught on that if she didn't want to be alone, she had to do her business outside.