Simple tutorial program does not work as expected

I am a newbie with MonoDevelop and C#, but I am a programmer of long experience. I have just started using MonoDevelop 2.6 on Ubuntu 11.10 to try to learn C# programming. I am following a tutorial. The first program, Hello World, works exactly as expected.

However, the second program is supposed to write a prompt and accept some input from the user. The program runs to successful completion, but does not pause to accept the user input. It then prints the output as if a NULL input had been accepted. Here are the program lines giving the problem:

            Console.WriteLine("Please enter a new first name:");
            firstName = Console.ReadLine();
            Console.WriteLine("New name: " + firstName + " " + lastName);

It is the second line that is not behaving as expected. Is the tutorial wrong, or is MonoDevelop misbehaving?