[nom-dun-chien]

Lenny, our 11 month old Yorkie, has taken to biting in the past couple of months - passers-by, cyclists, people in the street who try to pet either him or our other dog, Cookie. He actually bit my husband one night as he arrived home on his bike - without looking to see who it was he just lunged and nipped. But otherwise he never bites us or the kids (aged 12 and 7).
Here are a sample of the biting incidents:
One time, he bit a friend of mine on the shoulder when I greeted her in the street with a kiss on the cheek. ( Vet said I shouldn't approach people when holding him in my arms as this is frightening for him.)
On another occasion, he charged 150 yards across an empty park and had a go at a couple who were just walking along minding their own business.
He also bit a teenage boy who was cycling in front of our house.
In all he has bitten about seven times and now we daren't let him off his lead if other people are around.
He and Cookie, a 4 year old male mongrel who is twice his size, get along fine. They play together a lot and although there is growling and nipping involved they both seem to know the limits without us having to intervene. Cookie never bites although he barks very nastily when people walk past our house. The two dogs have human company most of the day since either myself or my husband are around much of the time. We feed the dogs in their own bowls after we have eaten ourselves, never from the table, and we don't allow them on our bed.
Any advice would be greatly appreciated. Thanks, Alison