Yes, no, maybe. 

If you listed an excluded driver on your policy, there is no coverage for that person if they drive your car. 

If the person you are loaning your car to is not excluded, there should be coverage.  Again, you need to talk to your agent to discuss your policy coverage and limitations. 

Anyone living in your house that is of driving age must be included on your policy or excluded.  The thought behind this is that everyone living in your house has regular access to your vehicle.  This poses a risk to the insurance companies.  If you loan your car to someone in your house and they are not mentioned on your policy chances are there will be no coverage if they are involved in an accident. You need to disclose any roommates or drivers in the house and they need to be added or excluded.

If you loan your car to someone who does not live with you, they are covered.  Again, any person you loan your car to is covered providing they do not reside in your house and do not have regular access to your vehicle.

Some companies will drop your liability limits to state requirements if you loan your car to someone and they are in an accident.  

You need to talk to your agent and review your policy limitations.