Why doesn't case-insensitive lookup through Q model work in django?

Question

Django

Everything is simple. In models.py there is a model of products and the search is done only by name:

class Product(models.Model):
    category = models.ForeignKey(Category, on_delete=models.PROTECT)
    brand = models.ForeignKey(Brand, on_delete=models.SET(1), default=1)
    title = models.CharField(max_length=120)
    ...

There is a view in views.py for searching (and import from above for it to work):

from django.db.models import Q

def client_search_view(request):
    query = request.GET.get('q')

    if query != None:
        products = Product.objects.filter(Q(title__icontains=query))
        context = {
            'title': 'Результаты поиска по запросу: ' + query,
            'products': products,
        }
    else:
        context = {
            'title': 'Введите строку поиска'
        }
    return render(request, 'client/client_search.html', context=context)

Naturally, there is a client_search.html template for this case, where the search form itself and the results loop are located:

{% extends 'base.html' %}

{% block content %}
    <h3 class="text-center">{{ title }}</h3>
    <form action="{% url 'client_search' %}">
        <div class="form-group">
            <input type="text" class="form-control" placeholder="Вот в этой строке" name="q">
            <button type="submit" class="btn btn-info"><i class="glyphicon glyphicon-search"></i>&nbsp; Искать</button>
        </div>
    </form>
    {% if products %}
          {% for product in products %}
            ....
          {% endfor %}
    {% else %}
        <h3 class="text-center">По заданному запросу изделия отсутсвуют</h3>
    {% endif %}
{% endblock %}

Well, everything seems to be simple.
Yes, by the way the sqlite database.
Django 2
Ubuntu 18
And now title__icontains doesn't work. The behavior is the same, as if it's just title__contains .
Those. for example I enter: radius - finds nothing I
enter: Radius - finds.
At first I thought he couldn't find it because the first word. I tried title_istartswith, but it still does n't seem to take this i into account.
What is the ambush? Maybe he does not know how to work with the Russian language? UTF-8 stands. Maybe sqlite limits? Maybe some nuance?
Sincerely.