"when we become" is correct and usable in written English.
For example, "When we become more knowledgeable, we should have more confidence in ourselves."
The system loves when we become individuals".
"When we become accountable to the capital markets, it's much healthier," he said.
Many issues would automatically resolve when we become an active part of the political system".
"If we're going to change the flag, let's do so when we become a republic".
"Then when we become financially better off, we move out here".
Are we misguided in relying on celebrities when we become sick?
"When we become doctors we can spread his influence," she said.
I will rejoice when we become averse to inflicting casualties on others.
"The choice of when we become a republic, should be our choice".
The evidence suggests we cease to care only when we become rich.
"When we become disheartened, we will be inspired by remembering how Wilma proceeded undaunted through so many trials and tribulations".
