Language / -ski/-ska, -scy/ski, -wicz - Polish surnames help [185]

I am doing some research on my Great Grandmother. She according to my mom always said that she was Lithuanian. Her maiden name was Boltnowicz according to her obituary but I cannot find any information on it. I know very little about surnames. Could there possible be an alternate spelling? She came over her from Russia in about 1905 and there are no record of her coming through Ellis island. Thanks for any help!