Final answer:
The belief of the hiker named Luke that his name brings him luck is an element of the exposition in 'Just a Little Lost', revealing character background and potentially hinting at future conflicts.
Step-by-step explanation:
The detail that the hiker named Luke believes his name makes him lucky is part of the exposition of the play 'Just a Little Lost'. The exposition serves to introduce characters, setting, and to hint at potential conflicts and themes.
From this detail, we learn about Luke's character and a hint at his worldview which may affect the development of the plot. The exposition can also involve revealing secrets from the backstory throughout the play via dialogue. Thus, Luke's belief in his luck could be leading up to a thematic exploration or conflict later in the narrative.