I found Nellie Lambertson, widow of Samuel, in the 1920 census of the 6th ward of Indianapolis, Marion Co., IN in the 1920 census. She was living on Illinois Street in the David Arms apartments on North Illinois street.
Her occupation was listed as a seamstress for a hotel. Nellie was aged 57, widowed, and born in Massachusetts. Her father was born in New York and her mother was born in Massachusetts.
I still need to discover what Nellie's maiden name was and find a record of her marriage to Samuel, which probably took place between 1909-1910 in either Hamilton or Madison Co., IN.