Yes, you can.
To do so, go to Exam Panel through your course by selecting Manage Course and then Exams from the left side menu.
Click on Manage Exam to go to your Exam panel and then select Edit Exam Info/Settings.
In the Exam must be taken after drop-down menu, select the lecture you'd like the exam to follow.
Please Note: In order for an exam to be considered part of the criteria for completing a course, it must be added to the lecture list in this way.