Share 'Dog Scared!!'

I adopted a poodle from the humane shelter about 3 weeks ago. He seems to be adapting to me and his new home very well. However, when I have adult company, he acts scared, almost petrified, and hides until company is gone. If it's a child visiting, he will growl at them when they come near. However, he will allow them to pet him if I hold him. (Otherwise, he's in hiding). Will he outgrow this beh…