Problem with looking to target OnMouseEnter

I want my game object to look at me when I hover over it with the mouse, but I can't get it to work how I want. Instead of waiting until I hover, each of the gameobjects I attached the script to look at me right when I start it up. Here is my script:

 using UnityEngine;
 using System.Collections;
 
 public class hoverScript : MonoBehaviour {
     
     public Transform target;
     public string levelToLoad;
     public AudioClip soundhover;
     public AudioClip beep;
     public int rotationSpeed;
     public bool QuitButton = false;
     public bool onHover = false;
     
     private Transform myTransform;
     
     //On Startup
     void Awake() {
         myTransform = transform;
     }
     
     void OnMouseEnter() {
         audio.PlayOneShot( soundhover);
         onHover = true;    
     }
     
     void OnMouseUp() {
         audio.PlayOneShot( beep);
         
         if( QuitButton) {
             Application.Quit();
         }
         else {
             Application.LoadLevel( levelToLoad);
         }
     }
     
     // Update is called once per frame
     void Update () {
             if( onHover = true) {
                 //look to camera
                 myTransform.rotation = Quaternion.Slerp( myTransform.rotation, Quaternion.LookRotation( target.position - myTransform.position), rotationSpeed * Time.deltaTime);
             }
     }
 }

I'm guessing it has something to do with the booleans, but I can't figure it out. If someone else could help I would really appreciate it!