Smart puppy! You may have to use petting and praise instead of treats. Does he have any toys you take with you for him to play with outside? Do you act excited about going out with him? If you're reluctant he will pick up on that and think it's going to be a bad experience. If he associates going outside with something fun and pleasant, it will be easier - until he wants to go outside to play all the time! Better that than peeing in the house, though.
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.
A lot of it depends on the times you take your dog out aswell.
You should take him out when he is most likely to want to pee such as after mealss, whens he wakes up or after he has had a drink.
When he goes for a pee outside praise him and let him know he's done it right.
Also try to have a signal that you can give him when you want him to go pee.
With my dogs every time they urinated outside I used a word for it, so while they were peeing I'd say "you having a wee"
Now every time I say "go have a wee" they know what I want from them.
It worked for me.
Don't panic too much if Luke messes up occasionally even after he's pretty much trained. I don't know why she did it, except maybe because it was cold outside, but yesterday morning I was working on the computer on a report and all of a sudden I heard water running. I thought a pipe had burst! Shiva had squatted right in the middle of the living room floor. Her bladder must hold a full pint. She went straight outside and after that spent the balance of the morning in the laundry room.
I just resoved to the fact that some dogs will do it just to be mean.
Most the time my dogs go outside, but everynow and then.... uh-oh.
And they know they did bad because they run and hide when they see
me coming. I think some just do it on purpose because they can.
You're absolutely right about that! I've seen it more with small dogs than large dogs; I have no idea why.
I think Shiva's faux pas had something to do with newspapers. When she was little and couldn't hold it all night I put newspapers down at the far end of the laundry room and she learned to use the newspapers. She and Bimmer had been playing while I was working and had knocked a stack of newspapers onto the floor. She peed right next to them. I think she was busy playing and just reverted to her baby habits. Our first Fila, Buffy, was STUBBORN, but Shiva is as opposite from Buffy as can be; so I'm inclined to believe this was just an accident, as she is still very much a baby at heart. It's hard to remember that she is still a baby sometimes, as she is physically so large and isn't even 6 months old yet. At this age, Buffy acted like a mature adult dog, where Shiva's disposition is still very puppy-like. She figured out how to open the storm door to go out yesterday and got so excited she forgot to walk through it until she'd finished jumping up and down on me in glee.