No, you are not obligated to name Arduino in the name or description of your course. However, it's useful for the customer to know which technology they are using. If you do mention Arduino, you must do so in a way that does not suggest that the course you are offering is officially endorsed, approved, or certified by Arduino.
- Permissible “Programming Course based on Arduino”, “Robotics Workshop for Arduino”
- Non-Permissible “Arduino Programming course”, Arduino Robotics Workshop”