If statements and Dates in R

What I am trying to achieve is allocate a new column with a variable that changes over time. It is just one of them that is changing so what I would like to do is After (date) put 40 instead if 22

I currently have this Code that is not working properly

Idea:
    if(lst$taskDate <= as.Date("2018-11-18")){
    t2$Budget <- case_when(
        t2$taskStaffName == "L" ~ 20,
        t2$taskStaffName == "J" ~ 22,
        TRUE ~ 40
    )
    }else{
        if(lst$taskDate >= as.Date("2018-11-19"))
    t2$Budget <- case_when(
        t2$taskStaffName == "L" ~ 20,
        t2$taskStaffName == "J" ~ 40,
                TRUE ~ 40

    )
        }


This is the Data Sample:

# A tibble: 3,692 x 4
   taskStaffName taskDate   taskMinutes taskBillable
   <chr>         <date>     <chr>       <chr>       
 1 G             2018-07-02 300         true        
 2 G             2018-07-02 180         true        
 3 L             2018-07-02 300         true        
 4 L             2018-07-02 180         false       
 5 C             2018-07-02 360         false       
 6 C             2018-07-02 120         false       
 7 G             2018-07-03 480         true        
 8 L             2018-07-03 30          true        
 9 L             2018-07-03 180         true        
10 L             2018-07-02 30          true        
# ... with 3,682 more rows



Desired Outcome:

# A tibble: 3,692 x 5
   taskStaffName taskDate   taskMinutes taskBillable Budget
   <chr>         <date>     <chr>       <chr>         <dbl>
 1 J             2018-07-02 300         true             22
 2 J             2018-07-02 180         true             22
 3 L             2018-07-02 300         true             20
 4 L             2018-07-02 180         false            20
 5 C             2018-07-02 360         false            40
 6 C             2018-07-02 120         false            40
 7 L             2018-07-03 480         true             20
 8 L             2018-07-03 30          true             20
 9 J             2018-11-19 180         true             40
10 J             2018-11-19 30          true             40
# ... with 3,682 more rows