Random Quote Machine - how to avoid quote repetition

my question is about a Quote generator I am working on. It's working also onload :), But I would like to omit the situation when the next onclick randomly picked quote is the same as the last shown quote. I would like it to be different. Thank You for Your hints.

this is my js code:

var quotes = [
  { text: "Memento mori", 
   autor: "Bractwo Męki Pańskiej" },
  {
    text: "Jeśli możesz sobie coś wymarzyć, możesz też to zrobić.",
    autor: "Walt Disney"
  },
  {
    text: "Wszystko jest możliwe. Niemożliwe wymaga po prostu więcej czasu.",
    autor: "Dan Brown"
  },
  {
    text: "Czerp z innych, ale nie kopiuj ich. Bądź SOBĄ",
    autor: "Michel Quois"
  },
  {
    text: "Kiedy łamiesz zasady, łam je mocno i na dobre.",
    autor: "Terry Pratchett"
  }
];

window.onload = function() {
  quoteMachine.initialQuote()
};

var quoteMachine = {

initialQuote: function() {

var newInitialQuote = quotes[Math.floor(Math.random() * quotes.length)];

var newInitialQuoteText = newInitialQuote.text;
var newInitialQuoteAutor = newInitialQuote.autor;

    document.getElementById("new-quote").innerHTML = newInitialQuoteText;
    document.getElementById("autor").innerHTML = newInitialQuoteAutor;
  }
};

This is the working example: https://randome-quote-machine.glitch.me