public Articles GetByName(string name, Categories category, Companies company)
{
var query = from article in session.Linq()
where
Use string.Equals(name, article.Name, StringComparison.OrdinalIgnoreCase) when you are sure that your database supports it.
E.g. SQLite with a collate of NOCASE will ignore the option. Oracle uses session settings NLS_COMP, NLS_SORT that will be taken.
Else use ToLower() or ToUpper() when you have no culture issues.
Use String.Equals
with the appropriate parameters to make it case insensitive
mySource.Where(s => String.Equals(s, "Foo", StringComparison.CurrentCultureIgnoreCase));