How can I login to my Telegram account when I lost my phone?

If I want to answer it in one sentence, it's not possible to log in to your account on a PC without your phone. However, you can follow these steps to get back your account:

1. Go to your SIM company and ask their help to recover your lost SIM.
2. Insert the SIM into any smartphone and log in to your Telegram account using that smartphone.
3. Now you have a phone with logged-in your account. So, using it, you can easily log in to your account on a PC.

I hope this helps to solve your issue. Let me know, if you need any further assistance.