You will want to call several insurance companies to compare rates. From company to company there is often a great difference in premiums. Some even give discounts for having auto and home coverage with the same company.
Once you have chosen the insurance company make sure to give this information to your mortgage broker and title company.
All lenders will require you to have homeowners insurance in place at the time of closing. You will pay for your first year up front at closing. If your mortgage is escrowing your insurance and taxes, they will collect several months to put in reserves at closing.
If it is hurricane season, be sure to secure your homeowners policy as soon as possible. Once a hurricane enters the Gulf of Mexico, insurance companies won't issue new policies in Louisiana, which could delay your closing.