"L'étudiant mange une orange."
Translation:The student eats an orange.
élève is what you'd use for elementary through to high school, étudiant is used for higher education students.
You're mostly right. However, eleve can also be used for doctoral students (c'est un 'élève d'Einstein' for instance) and for higher education students in general (we often talk about 'anciens eleves' for the "former students). So i would rather say that eleve is a general term, while etudiant is only for higher education student.