To activate your new Stellar account, you need to have at least 1 XLM on it. This rule is enforced by the Stellar network (not LOBSTR).
Please read more about it here: https://www.stellar.org/developers/guides/concepts/fees.html#minimum-account-balance
Certain exchanges and wallets won't send transactions to inactive accounts (with zero lumens balance), which can be confusing for new users and make initial funds receiving more complicated.
To make things easier for you, LOBSTR provides you with 1.5 XLM interest-free loan to activate your Stellar account at its creation moment.
You'll need to return the 1.5 XLM loan once you deposit more lumens to your account.
Use the 'Buy lumens' option in LOBSTR wallet or go through one of the popular exchanges.
Until 1.5 XLM loan is paid off to LOBSTR, you'll not be able to enable multisig or merge your account.
If your account is inactive for more than 30 days, it may be deleted by LOBSTR to return the loan. You will receive multiple email warnings in advance.
If you do not want to receive the 1.5 XLM loan, you can generate a key pair for a new account using Stellar Account Viewer (Click the 'Generate' button).
These keys can be imported into LOBSTR but your Stellar account will be inactive and will need to be activated with minimal 1 XLM payment.
How to return the loan?
In order to return the loan, you should have 3.01 XLM in your account at the very least and make sure none of it is taken up by the network reserve (minimum balance) or involved in active trading orders.
To return the loan in the web app, push the 'Pay Off Loan' button on the Home page or on the Settings page.
To return the loan in the mobile apps, tap on the 'Press to return 1.5 XLM credit' button on the Home screen.