So it turns out essential oil may not actually be such a great idea in your kitty's care. Long story short, they can't metabolize and eliminate compounds they inhale with that delectable aroma. There's a well-explained page on it here at The Lavender Cat. This includes a list of therapies that you might come across which actually are no good for puddycat: "Many make the mistake of applying an essential oil dosage suitable for a human baby to a cat, thinking that, due to its small size, if it is safe enough for a baby, it must be safe for cats. Babies do not have a cat's liver!" Even if your cat IS your baby.
I couldn't help but free-associate the words "Laveder" and "Cat" and had a dreamy yen to see a cat in Provence, land of lavender... Well here's a cute one.