SQL query to return only if upper case

I would like to make a query in a column and that the return would be only the capitalized words that match the searched criteria (user input), regardless of whether the criteria was typed in uppercase or lowercase.

CREATE PROCEDURE uspConsultaSobrenome

@Sobrenome nvarchar(MAX)

AS
   BEGIN

   SELECT

   SobrenomeID, 
     Sobrenome  
        FROM
            tbl_Sobrenomes
        WHERE 
        Sobrenome LIKE @Sobrenome + N'%'
END

I did so and the answer is both lower case and upper case.