For a little history to explain what I'm talking about - read this first.
I took my cat to the vet again yesterday. Actually, I took both of our cats to the vet yesterday, even though we were only treating Zephyr (aka Orange). We have to take both of them to the vet each time because otherwise one cat will come home smelling different and they act like they don't recognize each other for a couple of days. Lots of hissing and fighting is involved.
Anyway - the good news is that Zephyr/Orange has a urinary infection. Why am I happy about this? Well, this would explain why he's been marking or peeing everywhere. So yeah, we have a cause and we can treat this. The thought is that once we get his infection gone, he will go back to his usual behaviors of using the litter box.
Keep your fingers crossed. Mine are.