How would I Implement a 5 seconds Delay into my Loading Screen for Unity Free

Ive got code here that works as a basic loading Screen but I'm look to put a time delay on my version of code but i don't know how to implement it. I want my loading screen to stay on screen for at least 5 extra seconds because when i load some scenes the loading screen goes on and off the second with in a flash.

 using UnityEngine;
 using System.Collections;
 
 public class LoadingScreen : MonoBehaviour {
 
     //A Check for if its loading.
     private bool loading = true;
 
     //For GUI Section
     public Texture loadingTexture;
     public Texture[] gunTextures;
 
     //Font Style also for GUI Section
     public GUIStyle fontStyle;
 
     // For GUI Section
     public int keyframePointer = 0;
     public int keyframePointer1 = 0;
     public int keyframePointer2 = 0;
 
     //For Time Delay in seconds
     public float delay = 5.0f;
 
 
     void Awake () {
         
         DontDestroyOnLoad(gameObject);
         
     }
 
     void Update () {
         
         if(Application.isLoadingLevel){
             
             loading = true;
 
             keyframePointer = Random.Range(0, 112);
             keyframePointer1 = Random.Range(0, 112);
             keyframePointer2 = Random.Range(0, 112);
 
         }
         else{
 
             loading = false;
 
         }
         //keyframePointer = Random.Range(0, 60);
         Debug.Log(keyframePointer);
     }
     
     void OnGUI () {
         
         if(loading){
 
             float halfHeight = gunTextures[keyframePointer].height;
             float halfHeight1 = gunTextures[keyframePointer1].height / 2;
             float halfHeight2 = gunTextures[keyframePointer2].height / 2;
 
             GUI.DrawTexture(new Rect(0,0,Screen.width + 4,Screen.height + 4), loadingTexture);
             GUI.Label(new Rect(Screen.width - 340, Screen.height - 68, 300, 34), "Loading...", fontStyle);
 
             GUI.DrawTexture(new Rect(Screen.width / 2 - 128, Screen.height / 2 - halfHeight1, gunTextures[keyframePointer1].width, gunTextures[keyframePointer1].height), gunTextures[keyframePointer1]);
             GUI.DrawTexture(new Rect(Screen.width / 2 - 32, Screen.height / 2 - halfHeight, gunTextures[keyframePointer].width * 2, gunTextures[keyframePointer].height * 2), gunTextures[keyframePointer]);
             GUI.DrawTexture(new Rect(Screen.width / 2 + 96, Screen.height / 2 - halfHeight2, gunTextures[keyframePointer2].width, gunTextures[keyframePointer2].height), gunTextures[keyframePointer2]);
 
 
         }
 
     }
 
 }