I don't know what your application does or why it would lower-case things. But, I don't think there is a good solution for that on the SQL side of things. You could query the schema information and you can match that by specifying the collation. But, that would require you to query the schema information every time for every table to get the correct casing for each table and column name in that database.
The obvious alternative is to adjust your application to handle it or ask the client to change their DB or walk away from the project if it is going to cost you too much money to adjust your app.