Two possibilities here and one is a urinary tract infection keeping him from controlling when he needs to go.
The other would be puberty and the strong minded lhasa temperament 'squirting out' as he marks your home with his urine because he thinks he runs the world.
For the first a check of a urine sample or bloodwork for kidney function might be a good idea.
For the second, training, demoting him to not being the new pack leader, training, supervision, and did I mention training? :)
Basic obedience training as well as using the nothing in life is free program may help him a lot.
www.apdt.com may help you locate local training classes.
And this site goes over the nothing in life is free program
www.goletavet.com/nothingfree.html
You should also clean up any areas he has hit with urine using an enzyme based cleaner such as Simple Solution, Odor Mute, Nature's Miracle to eliminate the odor that draws him back there to go again.
Hope this helps you!
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