Travelling with Hortense was 3 year-old Pierre Nossent, presumably her son.
As unusual as their surname is, it must be him in the 1930 census in Jackson, Washington, OK: head, Pete Joseph Nossent, 24, Belgium wife, Louise L., 17, OK
There is a Pierre Nossent in the SSDI; b 22 Nov 1905, d 1 Jan 1976, last residence Tulsa, OK. This is a good match for a 3 year-old arriving in the U.S. in August 1909. Try http://www.tulsalibrary.org/centralhttp://www.tulsalibrary.org/central for a copy of his obit.