Lutherans do not typically use the language "need to be baptized to be saved," as this indicates a law view of Baptism. We do not think of Baptism as law but as gospel, that is, Baptism is not something man does out of obedience or requirement, but that Baptism is God's work, performed by the hands of the body of Christ on earth, to grant salvation and faith in Christ.
When an adult or older child comes to faith through hearing the gospel, they are typically instructed for a time in the faith and then baptized. Baptism still gives what scripture says it gives whether it is the means of granting initial faith in Christ or the means of strengthening faith in Christ that is already present. However, for someone to say that they believe in Christ and yet refuse God's gift of Baptism would indicate a concerning doctrinal misunderstanding and a need for pastoral care.